Ginger Could Be the Key to Saving the Stag Beetle

The stag beetle is the largest terrestrial insect in the United Kingdom but finding the elusive species has always been a challenge. Conservationists fear that the beetle's numbers may be declining but without an accurate count of the population, no effective protection plan can developed.

Fortunately, new research suggests that a simple solution—using everyday ginger—could make counting stag beetles easier.After testing several other fruits and vegetables, beer and wine, and light traps, the team finally stumbled upon the winner. Ginger, they found, makes an irresistible bait for stag beetles.

Our new methods offer genuine promise for monitoring the population of this elusive and rare insect, one that we think is declining across much of its European range. We need to know where the stag beetle lives—and in what numbers—to be able to conserve it effectively.

By using ginger, Harvey and her team were able to produce a simple, cost-effective, trap for attracting stag beetles.

Counting the adult population alone, however, was not sufficient. The team also needed to find a way to count the subterranean populations of larvae. "Sampling subterranean insects without destroying the larval habitat is notoriously difficult," Harvey explained.

To solve the problem, the team re-purposed diffusive samplers—typically used for measuring environmental pollution—to detect longifolene, a chemical emitted by the larvae. Longifolene is also emitted by plants, so the team added tiny microphones to detect the subtle vibrations of the larvae.

Used in conjunction with one another, the tools provide a cheap and accurate means of counting the larvae that doesn't require the disruption of their underground homes.

The technique, Harvey said, is underused in the field but could be a valuable tool for measuring a large range of insect species.

The stag beetle is the largest terrestrial insect in the United Kingdom but finding the elusive species has always been a challenge. Conservationists fear that the beetle's numbers may be declining but without an accurate count